A semiconductor light emitting device such as an LED is a device including a material that emits light using electric energy, in which energy generated through electron-hole recombination in semiconductor junction parts is converted into light and emitted therefrom. LEDs are commonly used as light sources in lighting devices, display devices, and the like, and development of LEDs has thus been accelerated.
In particular, the recent increase in development and use of gallium nitride-based LEDs and the commercialization of mobile keypads, turn signal lamps, camera flashes, and the like, using such gallium nitride-based LEDs, has led to accelerated development of general lighting devices using LEDs. Applications of LEDs are gradually moving from small portable products toward larger products having high output and high efficiency, such as a backlight unit of a large TV, a vehicle headlamp, a general lighting device, and the like. Accordingly, light sources satisfying requirements for corresponding applications are in need.
As the applications of semiconductor light emitting devices are extended, a method of improving reliability of semiconductor light emitting devices is being required.